1. Field of the Invention
This invention relates to a system and method for engraving using multiple engraving heads, and more particularly, to an engraver having multiple engraving heads for engraving a substantially continuous, intermeshed or blended engraving pattern using multiple engraving heads.
2. Description of Related Art
The electromechanical engraving of a gravure cylinder involves rotating a cylinder while actuating an engraving head, or engraving heads having a diamond stylus carried on an oscillating shaft. The stylus cuts or engraves cells, lines of cells or tracks into the surface of the cylinder to produce an engraved cylinder for use in a printing process. The engraved cylinder is normally used in a web-type gravure printing press for printing paper, plastic, metallic film material, or other printed material.
In engravers for engraving cylinders used for printing publications, such as magazines or the like, the engraver may include multiple engraving heads wherein each engraving head includes a diamond stylus. By providing multiple heads, each head may be used to engrave different portions of the cylinder wherein each portion of the cylinder engraved by a respective head may, by way of example, correspond to a different page of the publication.
The movement of the styli for performing the engraving operation is precisely controlled to ensure that the engraved cells, or lines of cells or tracks formed by each engraving head are located at the desired positions on the cylinder. However, the initial positioning of the engraving heads relative to each has historically been very labor intensive wherein a skilled worker manually adjusts the position of each engraving head prior to an engraving operation.
Because of the manual intervention and because the styli of each engraver head wears differently, varying copper hardness in the surface of the cylinder, and differences in engraving response, characteristics of each engraving head and the like, it was difficult to use two or more engraving heads to engrave a continuous pattern. The cells or areas engraved by the different heads would not match-up, thereby creating an undesirable seam in the cylinder which may subsequently cause a visible printing defect.
Accordingly, there exists a need for a system and method for enabling multiple or a plurality of heads to be used in engraving operations such that the heads can cooperate to engrave a continuous blended and/or intermeshed pattern.